Electric switch



Feb. 6, 1934. A. J. DAWE ELECTRIC SWITCH Filed May 6, 1931 I Illlllil m IN VE N TOR A/L /EFf 1/: D5WE BY JWWW A T TORNE Y Patented Feb. 6, 1934 UNITED STATES PATENT OFFICE ELECTRIC SWITCH Application May a, 1931. Serial No. 535,414

9 Claims.

This invention relates to certain new and useful improvements in electromagnetically actuated switches.

In switches of this character, it is customary to mount the movable contactor or contactors from a pivotally mounted armature for movement into engagement with the stationary switch contact or contacts upon the attraction of the armature to an electromagnet. I

The armature, and consequently the movable contactor or contactors carried thereby, is held in its open position, either entirely by gravity or by suitable spring means, and as, for commercial purposes, the electromagnet is comparais tively small, such springs are of necessity, light. Vibration to which switches of this nature are often subjected'thus, is apt to cause the armature to chatter and accidently close the switch. Such accidental closure of the switch, arising 2') either from vibration to which the switch is subjected, or from any other source, is obviously objectionable, and it is therefore one of the objects of this invention to provide novel means for positively precluding closure of the switch.

It is another object of this invention to provide means for preventing accidental closure of the switch, which means is of unitary construction and applicable to switches either at the time of their manufacture or after they have been in service, without in any way disturbing the structure of the switch.

Another object of this invention is to provide a novel armature stop mechanism for electromagnetically actuated switches which embodies a movable element normally preventing closing of the armature and which movable element is quickly moved out of its operative position upon energization of the solenoid prior to the movement of the armature toward closed position.

A further object of this invention resides in the provision of means for preventing accidental closure of an 'electromagnetically actuated switch which incorporates a stop abutment engageable by the armature and receiving positive support from the stationary structure of the switch to prevent forced closure of the armature. A still further object of this invention is to provide a unit readily applicable to switches either at the time of their manufacture or at any later date,

which combines the functions of a coil retainer to hold the solenoid in position and also serves as the movable stop to prevent closing of the armature.

With the above and other objects in view which will appear as the description proceeds, my invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claims.

In the accompanying drawing, I have illustrated one complete example of the physical embodiment of my invention constructed according to the best mode I have so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a side elevation of an electric switch structure embodying this invention;

Figure 2 is a cross section view taken through Figure 1 on the plane of the line 22;

Figure 3 is a front view of a portion of the magnet structure illustrating in detail the position of the latch mechanism; and

Figure 4 is a perspective view of the combined coil retainer and movable armature stop shown detached from the switch structure.

Referring now more particularly to the accompanying drawing, in which like numerals designate like parts throughout the several views, the numeral 5 represents the supporting frame of a substantially U-shaped electromagnet core having spaced poles 6 and 7. The pole 6 provides support for a conventional solenoid 8 adapted to be 35 energized to attract and pull in a movable armature 9, pivotally mounted as at 10 from the frame 5.

The faces of the poles 6 and '7 preferably lie in closely adjacent parallel planes and the pivotal mounting 10 is so disposed that when the armature is in its fully closed position, its inner surface engages the face of the pole 6 and lies parallel with the face of the pole 7.

Carried by the armature is an insulating bar 11 from which one or more contactors 12, are mounted for engagement with cooperating stationary contacts 13, carried by a supporting base 14 from which the entire switch structure is mounted. It is observed that the armature is so mounted that gravity normally holds the same open. and if desired, a light coil spring 15 may be provided at the pivotal mounting 10 to assist in maintaining the armature open.

The opening movement of the armature may be limited in any suitable manner, and in the present instance, an arc hood 16, shown in light construction lines, is carried by the support for the stationary contacts or any other suitable supporting structure, to substantially enclose the cooperating switch elements and limit the outward movement of the contactor. The are hood 16, however, forms no part of this invention and it is therefore not shown nor described in detail.

Irrespective of what means is employed to hold the armature in a predetermined open position, the armature, in its open position, must be sumciently close to the pole faces to enable the magnetic pull of the solenoid to draw it in". The distance between the switch contacts is thus comparatively small, and as the spring 15 is of necessity weak, the excessive vibration to which these switches are often subjected, causes the armature and movable oontactor carried thereby to chatter to such an extent as to accidently close the switch.

Obviously, such accidental closure of the switch is highly objectionable and this invention eliminates the possibility of accidental closure by the provision of a novel stop mechanism indicated generally by the numeral 17, and shown in detail in Figure 4.

This stop mechanism consists of a support ing plate 18 of light, relatively flexible sheet metal having a central rectangular opening 19 to enable its engagement over the outer end of the pole 6. At its opposite ends the rectangular opening 19 has outstruck flanges 20 provided with medial openings or slots 21. These flanges 20 lie againstthe sides of the pole piece 6 when the plate 18 is positioned over the pole piece, and the slots or openings 21, align with a transverse opening 22 in the outer end portion of the pole piece. A cotter pin or other suitable securing member 23 is then inserted in the opening 22 to retain the plate in position.

The plate 18 thus not only serves as a support for the latch mechanism, but also holds the solenoid against detachment, and to take up play between the solenoid outer face and the cotter pin 13, the supporting plate is slightly bent as at 24, to exert an outward tension at its medial portion as will be readily apparent. One side of the plate, preferably the bottom thereof, is cut away, as at 25, to prevent an inductive action on the part of the plate.

Projected outwardly from one lower corner of the plate is a mounting stud 26 which pivotally mounts a lever-like member 27. The lever member 27 is formed of magnetic metal and, being positioned directly adjacent and beneath the pole 6, forms an armature movable toward the pole upon energization of the solenoid.

At the outer free end of the lever 27 a stop member 28 of non-magnetic metal extends downwardly. The stop member 28 has its outermost extremity of reduced width and ofiset as at 29 to project over the face of the adjacent pole piece 7 and at one side of the offset portion 29 is a laterally directed flange 30 which forms a stop abutment to prevent inward movement of the main armature 9 beyond a predetermined degree as will be hereinafter more fully described.

A light coil spring 31 having extended ends encircles the pivot stud 6 and has one end engaging the undersurface of the pole piece 6 and has its other end engaging an inwardly directed flange 32 on the inner edge of the stop member 28. This coil spring 31 yieldably urges the lever 27 downwardly and away from the pole piece 6 and such movement of the lever 27 is limited by the engagement of the flange 32 with the adjacent upper surface of the pole piece 7.

It is noted that the lever 27 moves in a plane inwardly of the outer ends or faces of the pole pieces so as not to conflict with the main armature in its fully closed position, and that when the lever 27 is in its position engaging the oifset portion 29 of its stop member 28 over theouter face of the pole piece 7, the offset portion 29 receives rigid support from the pole piece 7. The lateral flange or abutment 30 carried by the ofiset portion is thus positioned between the pole 7 and the armature 9 and as it receives rigid support from the pole piece it positively precludes closing of the main armature unless the lever member 27 is moved upwardly to carry the abut ment 30 out of the path of the main armature.

As stated, the lever member 27 is formed of magnetic metal and therefore forms an armature to be attracted to the pole piece 6 upon energize.- tion of the solenoid 8, and as it lies considerably nearer the pole piece 6 and has very little mass or inertia to overcome in comparison to that of the main armature 9, it follows that the lever 27 is pulled in" to move the abutment 30 out of the path of the main armature before the main armature begins its closing movement.

From the foregoing description taken in connection with the accompanying drawing, it will be readily apparent to those skilled in the art to which an invention of the character described appertains, that the armature stop mechanism of this invention provides positive means for preventing accidental closure of a magnetically actuaied switch, and is automatically releasable upon energization of the solenoid to close the switch; and further that the stop mechanism is readily detachable from the switch structure as a unit, is self supporting, and is equally applicable to switches already in service as to switches at the time of their manufacture, and that its application does not require additional elements or alterations in the design of the switch, as it utilizes an existing part of standard switch construction to mount the mechanism, and acts in conjunction with other existing parts to effect the desired result.

What I claim as my invention is:

1. In combination with an electromagnet having spaced pole pieces and a solenoid, an armature movable to the pole pieces to closed position upon energization of the solenoid, a movable stop having a part normally overlying one pole piece in the path of the armature to be positioned between said pole piece and the armature and prevent accidental closure of the armature, and means to automatically move the stop out of the path of the armature upon energization of the solenoid.

1 2. In combination with an electromagnet having spaced pole pieces and a solenoid, an armature movable to the pole pieces to closed position upon energization of the solenoid, and a pivotally mounted stop member having a part normally overlying one of the pole pieces in the path of the armature to be positioned between said pole piece and the armature and prevent accidental closure of the armature and another part forming a second armature disposed adjacent the other pole piece, said second armature being of less mass than the first mentioned armature whereby energization of the'solenoid attracts said second mentioned armature to move the stop member out of the path of movement of said first mentioned armature prior to the initial closing movement of the first mentioned armature.

3. In combination with an electromagnet including spaced pole pieces, an armature mounted for movement to and away from the pole pieces,

a solenoid mounted on one of the pole pieces and adapted upon energization to attract the armature to the pole pieces, a movable stop for preventing accidental movement of the armature to the pole pieces, and common means carried by the pole piece having the solenoid mounted thereon for retaining the solenoid on said pole piece and mounting the movable stop.

4. In combination, an electromagnet including a core and a solenoid loosely mounted on the core. an armature adapted to be attracted to the core upon energization of the solenoid, a movable stop for preventing accidental movement of the armature to the core, a supporting member for the movable stop engaged over the core to detachably hold the solenoid thereon, and readily detachable means for maintaining said supporting member on the core.

5. In combination with an electromagnet including a core having spaced pole pieces, a solenoid removably supported from one of the pole pieces, an armature movable to the pole pieces upon energization of the solenoid, a substantially fiat plate readily detachably mounted on said pole piece outwardly of the solenoid to retain the solenoid in position, a lever of magnetic metal pivotally carried by said plate between the spaced pole pieces and movable in a plane inwardly of the outer ends of the pole pieces, an abutment carried by said pivoted lever and adapted to overlie the other of said pole pieces in the path of the armature to prevent complete movement of the armature to the pole pieces, and spring means yieldably maintaining said lever in a position holding said abutment in operative position, and said lever being of less mass than the armature to be attractable to the first mentioned pole piece upon energization of the solenoid before the armature begins its movement to the pole pieces.

6. In combination with an electromagnet having a core provided with a pole piece and an armature movable to the pole piece, a coil loosely mounted on said pole piece, an apertured plate readily detachably mounted on the outer end of the pole piece to hold the coil thereon, a stop movably mounted on the apertured plate with a part normally overlying a rigid portion of the core in the path of the armature to receive positive support from said core portion and thus positively prevent accidental closing of the armature, and said movable stop having a part formed of magnetic metal whereby upon energization of the coil the movable stop .is drawn toward the pole piece and out of the path of the armature.

7. In combination with an electromagnet having spaced pole pieces and an armature movable to the pole pieces, a coil loosely mounted on one of the pole pieces, a washer readily releasably engaged over the outer end of said pole piece to hold a coil thereon, and a stop member movably mounted on the washer to have a part normally overlying the other pole piece in the path of the armature to positively prevent accidental closing of the armature, said stop member having a part formed of magnetic metal so that upon energization of the coil the stop member is attracted to the first mentioned pole piece to carry its armature engaging part out of alignment with the armature.

8. As an article of manufacture, a combined coil retainer and armature stop for electromagnets comprising, an apertured plate, a lever formed of magnetic metal, means pivotally mounting the lever on said plate, a spring coiled about the mounting means and engaging the lever to urge it in one direction, and armature blocking means on the outer end of the lever.

9. As an article of manufacture, a combined coil retainer and armature stop for electromagnets comprising, an apertured plate of sheet metal, a pivot post projecting from one face of the plate, a lever formed of magnetic metal pivotally mounted on said post to be movable toward and away from the aperture in the plate, and an arm carried by the free end of the lever to form a movable armature stop.

ALBERT J. DAWE. 

